Titanium dioxide-coated roof tiles clean the air—and have the data to prove it

Published on July 7th, 2014 | By: Jessica McMathis

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Feature image: At left, two tiles coated with the titanium dioxide mixture. At right, uncoated tiles. At top, a commercially available tile with titanium dioxide.Credit: UC Riverside

College students tend to get a bad rap.

Lazy college senior meme. Credit: Knowyourmeme.com

Having been one at one point (practically a lifetime ago—hello 10-year reunion!), I know that the majority of kids in college are not the hard-partying, misguided individuals they’re often pegged to be. In fact, most of them are responsible, young adults on the cusp of greatness—albeit greatness that comes at a high price. (Have you looked at student loan debt figures lately? Yikes. Good thing that ACerS offers a complimentary associate membership for one year following graduation. More info on that here.)

Students from the University of California, Riverside’s (UCR) Bourns College of Engineering have developed a roof tile coating that combats nitrogen oxides by breaking them down and eliminating them to reduce pollution and smog.

According to a UCR press release, their titanium dioxide mixture can handle the same amount of harmful nitrogen oxides emitted by a car driven 11,000 miles per year, and remove up to 97 percent of them from the air.

Led by David Cocker, professor of chemical and environmental engineering, and Kawai Tam, lecturer at Bourns, the team (which includes students Carlos Espinoza, Louis Lancaster, Chun-Yu “Jimmy” Liang, Kelly McCoy, Jessica Moncayo, and Edwin Rodriguez) applied the white coating to two identical clay tiles in different amounts and placed them in a mini atmospheric chamber made of wood, Teflon, and PVC piping.

The chamber—connected to nitrogen oxides and a device that measures their concentrations—used UV light to simulate sunlight.

The tiles coated with titanium dioxide were able to remove between 88 percent and 97 percent of the oxides. And interestingly enough, despite one tile having 12 times the amount of coating applied, the amount didn’t seem to make “much of a difference” in the removal. So though the idea of air-cleaning tiles may not be novel, having data to support the idea is.

The low-cost coating (they estimate that it would only cost $5—aka, a morning cup of coffee at Starbucks—to apply the titanium dioxide mixture to the average-sized roof) would be of benefit pretty much anywhere, but would make a huge impact in smoggy southern California—home to both UCR and America’s smoggiest city, Los Angeles—where 500 tons of nitrogen oxides are emitted each day. They calculate that if applied to one million homes, the coating would eliminate 21 tons of nitrogen oxides from the atmosphere daily.

The students, who received their diplomas this month, also received an honorable mention for the research as part of phase two in the Environmental Protection Agency’s student design competition. Last year, the UCR student team received $15,000 in the competition’s first phase.

The recent grads are hopeful that a new student team will continue the work in testing new variables (how long the coating will last, how color might impact its effectiveness) and a variety of applications (exterior paint, concrete, and freeway dividers).